I think you were in Puerto Madero last night. One thing I do like about wandering through there is the fact that there somehow seems to be free wifi floating about. The couple of times I've eaten at Cabana Las Lilas (once because the books all say you have to and the second time because I was super tired and lazy and was staying at the Hilton), I could use the wifi on my phone while dining.

There's a whole thread here about where to go for steak. I think the locals can tell you what's best. I believe http://www.parrillalacabrera.com.ar/ is quite popular. I also like http://www.campobravo.com.ar/ which has two locations in Palermo (a part of town you should visit). I like them both equally well.

Cafe Tortoni was nothing terribly extraordinary to me but the history and ambiance of the place was interesting and worth the visit.

Make sure you get some empanadas while you're down there. I pretty much each breakfast at the hotel, eat empanadas throughout the day while I'm wandering about and then have a big bife dinner

If you head to Recoleta to wander and visit the cemetary, you should also drop by Cafe La Biela - particularly if the weather is nice. I didn't find the food all that interesting but it's great to sit out, have a drink and soak up the atmosphere - very nice if there are tango performers out and about.

If you see a "Freddo", drop in for some gelato. You've got to have the Dulce de Leche when in Argentina.

You're a tourist, it's your first time there - you might as well revel in the touristy things!